This proposal is to obtain a new commercial Zeiss ELYRA S.1 Super-Resolution Structured Illumination Microscope (SR-SIM) that has unique multi-channel super- resolution capabilities for a group of cell biologists studying the molecular architecture of processes including cell division, migration, polarity and organelle dynamics and inheritance. One of the major limitations of light microscopy for the study of cell structure and function has been the inability to resolve structures below the diffraction limit imposed on optica systems. The ELYRA S.1 SR-SIM uses structured illumination to generate images that exceed the normal resolution barrier by two-fold in both lateral (X, Y) and axial (Z) directions. The ELYRA S.1 SR-SIM provides a rare combination that is not found in other commercially available SR-SIMs: superior performance (user- friendly high-resolution 3D SIM imaging in three channels, and rapid live-cell SIM imaging) and low cost. The major users of the requested instrument are all experienced cell biologists who have made extensive use of light microscopic approaches in their past work. This group seeks to use the ELYRA S.1 SR-SIM to extend their NIH-funded studies to obtain higher-resolution information on processes such as the interaction of cytoskeleton with membranes, organelle genome structure and localization, kinetochore dynamics, and nuclear envelope structure. Collaborative interactions already exist within members of this group and this is expected to facilitate adoption of procedures and techniques that will enhance the utility of the super-resolution microscope. The instrument will be administered as part of an established and well-supported imaging center at Columbia University, which will facilitate broad exposure of the instrument to additional users. The higher-resolution information obtained with the ELYRA S.1 SR- SIM should extend our knowledge of fundamental cellular processes occurring below the resolution of our existing light microscopes. This information will be helpful in identifying new avenues for the development of therapeutic approaches for the treatment of diseases such as cancer, inflammation and heart disease that result in part from deficits in the proper organization of cellular architecture.